Physics - Online Test
Q1. Nine particles have speeds of 5.00, 8.00, 12.0, 12.0, 12.0, 14.0, 14.0, 17.0, and 20.0 m/s. find the particles’ average speed.
Answer : Option C
Explaination / Solution:
vav=∑vn=5.0+8.0+12.0+12.0+12.0+14.0+14.0+17.0+20.09vav=12.7m/sec
Q2. A bird flies down vertically towards a water surface. To a fish inside the water, vertically below the bird, the bird will appear to
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. The half life of radium is 1600 years. The fraction of a sample of radium that would remain undecayed after 6400 years is
Answer : Option D
Explaination / Solution:
No Explaination.
Q4. The triple points of carbon dioxide is 216.55 K. Express this temperatures on the Celsius and Fahrenheit scales
Answer : Option B
Explaination / Solution:
TK = 216.55K
after solving
TC = – 56.60 C
TF = – 69.88 F
Q5. A student measures the thickness of a human hair by looking at it through a microscope of magnification 100. He makes 20 observations and finds that the average width of the hair in the field of view of the microscope is 3.5 mm. What is the estimate on the thickness of hair ?
Answer : Option B
Explaination / Solution:
Magnification of microscope = 100 Observed width of the hair = 3.5 mm Estimate on the thickness of hair is given by
Magnification =
=> Real width = = = 0.035 mm
Q6. You have a special light bulb with a very delicate wire filament. The wire will break if the current in it ever exceeds 1.50 A, even for an instant. What is the largest root-mean-square current you can run through this bulb?
Answer : Option D
Explaination / Solution:
maximum value of current
root-mean-square current
Q7. The wire of the potentiometer has resistance 4 ohms and length 1 m. It is connected to a cell of e.m.f. 2 volts and internal resistance 1 ohm. The current flowing in the potentiometer is:
Answer : Option B
Explaination / Solution:
If the battery has an e.m.f E, resitance of the potentiometer is R and the internal resistance of the battery is r, then the current I flowing in the potentiometer wire is given as
Q8. For all practical purposes, the motion of a simple pendulum is SHM,
Answer : Option D
Explaination / Solution:
No Explaination.
Q9. In hydrogen atom, the electron is making rev./sec around the nucleus in an orbit of radius 0.528 Å .The magnetic moment () will be
Answer : Option B
Explaination / Solution:
Magnetic moment of the electron .The current due to the orbiting electron
. The magnetic moment
. The magnetic moment
Q10. A viewing screen is separated from a double-slit source by 1.2 m. The distance between the two slits is 0.030 mm. The second-order bright fringe m =2 is 4.5 cm from the center line. Distance between adjacent bright fringes is
Answer : Option D
Explaination / Solution:
No Explaination.
